Thank you for your interest on our products. This device is a combination metal wall plate with two types of openings. A GFI/Block opening and two blank openings. Each has it's own screw hole spacing.
Here are the screw hole spacing for each:
- (GFI/Block) device mounting (3.812 in. between mounting holes)
- (2 Blank) box mounting (3.281 in. between mounting holes)
The reason behind the screw spacing for block and blank wall plate openings is explained in the images below. For Decora/block devices, the wall plate usually mounts to the saddle of the wiring device and in most cases it's outside the box. This is by the way the reason why smaller screws are included with Rocker/GFCI wall plates. However, blank wall plates are meant to mount to the electric box itself and the mounting holes inside the electric box are spaced closer together.


I hope this helps.